Depends which kind. Artificial whoop-de-dos have nothing in common with their natural cousins. The big rollers popular with terrain-park rats occur in nature no more often than rainbow-shaped metal rails. They're built—on purpose—by a bunch of dudes shaping and smoothing a flat slope with snowcats and tillers, creating a wave train of symmetrical ridges that are nice for spinning 180s. Natural whoop-de-dos, on the other hand, occur when Satan, standing down in Hell, punches up at the snowpack with his pitchfork. Or so it seems on an undulating path like Snowbird's Cirque Traverse, or the spine-compressing goat track that is Taos's High Traverse. But, truth be told, natural whoops—like moguls—form when skiers ply the exact same route; their braking and snowplowing form troughs and crests that get more pronounced and harder to avoid with time and subsequent snowfall. Whoop-de-do paths, however, are generally accepted—like frostbite or a lousy sex life or cataracts—as character-building components of an existence dedicated to the sport of skiing. So suck it up.